Shiftable engine and propeller mounting for auxiliary powered sailboats



Sept, 15, 1953 E o HURST 2,652,019

SHIFTABLE ENGINE; AND PROPELLER MOUNTING FOR AUXILIARY POWERED SAILBOATS Filed April 27, 1951 INVENTOR EARL OLIVER HURST WWW/s ATTORNEYS Patented Sept. 15, 1953 UNITED STATES PATENT OFFICE SHIFTABLE ENGINE AND PROPELLER MOUNTING FOR AUXILIARY POW- ERED SAILBOATS 2 Claims.

This invention relates to sailboats which are equipped with auxiliary power, and, more particularly, to the reduction of propeller drag when the boat is operated und er sail power only.

The advantages of providing sailing craft with auxiliary power, such as an internal combustion engine, are well recognized, but the objection has been raised to the installation of auxiliary power because of its tendency to impair the sailing qualities of the boat. One of the chief factors tending to impair the sailing qualities is the drag induced by the propeller which is a necessary part of the auxiliary power equipment.

Efforts have heretofore been made to eliminate or reduce the drag of the propeller in such auxiliary craft, by providing a vertically movable sheathing or housing which could be lowered to enclose the propeller and form an extension of the keel, when it Was desired to operate the boat under sail only. Such arrange ments, however, are complicated and involve unwarranted cost of construction. An additional and greater objection to them, however, is the fact that they require one or more longitudinal slots in the bottom of the hull at the stern. These weaken the hull structure and are sources of annoyance because of leaks and the opportunity for rot because of inability adequately to paint the joints between these slots and the enclosures for these housings when they are in their upper and inoperative positions.

The object of the present invention is to provide a boat construction which substantially eliminates the drag due to the propeller but which does not involve changes which weaken the hull structure, and which also can be pro= vided at moderate cost of construction.

The-invention will be understood from an examination of the accompanying drawings which illustrate by way of example two embodiments thereof. In these drawings:

Fig. l is a View in side elevation of a sailboat embodying the invention;

Fig. 2 is a vertical transverse section taken on line 2-2 of Fig. 1;

Fig. 3 is an enlarged section showing a detail;

Fig. 4 is a longitudinal central vertical section drawn to a somewhat larger scale than Fig. 1 and including a modified form of the invention;

Fig. 5 is a fragmentary horizontal section taken on line 5--5 of Fig. 4;

Fig. 6 is a vertical transverse fragmentary section taken on line 6-6 of Fig. 4; and

Fig. '7 is a view in rear elevation looking in the direction indicated by the arrows 1-1 in Figs. 1 and 4.

Referring now to these drawings the sailboat shown in Fig. l which is provided with a mast and sail as indicated diagrammatically is also equipped with auxiliary power in the form of a small internal combustion engine unit I mounted in the interior of the boat and driving a propeller 2 by means of a propeller shaft 3. The construction of the boat may be chosen to suit the taste of the user, but for purposes of present illustration the hull 4 is of marine plywood and has a V-shaped bottom with a keel 5 having a deadwood section 8 extending from a point adjacent the stern to the fore part of the boat. Deadwood section 6 contains a channel extending lengthwise thereof for propeller shaft 3 and at the front end of this channel is the usual stuffing box.

At the rear end of deadwood section 6 a recess 1 is formed approximately as deep (dimension lengthwise of the boat), and preferably some-- what deeper, than the corresponding dimension of propeller 2. The full advantages of the illvention are obtained by also making the side walls of this recess to follow the general configuration or outline of the propeller in rear view as shown in Fig. 7. Recess i can conveniently be constructed by arranging the. rear portion of deadwood 5 so as to have on one side a removable section 8 which extends to the longitudinal center of the deadwood as shown in Fig. 7. One half of recess 1 may be cut out of the inner face of section 8, and the other half from the contiguous surface of deadwood 6. Section 8 may be secured in place by means of bolts 9 (Figs. 4 and '7). If desired, the rear portion of deadwood 6 may be constructed of suitable molded material containing recess 1 properly shaped to the configuration and dimensions of the propeller.

In the form of the invention shown in Figs. 1-3 inclusive, the auxiliary engine unit 5 is of high-speed light-weight design and includes in a single unit the engine proper, fuel tank, ignition equipment, exhaust muffler and clutch mechanism, operated by a lever Iii. The propeller shaft 3 is a continuous shaft extending from the propeller 2 to the engine unit to which it is permanently connected.

The engine unit is mounted for longitudinal sliding movement in the boat and can be readily moved by hand from the full line to the dot and dash line position shown in Fig. 1. In the full line position the propeller 2 is shifted to the rear, clear of the rear end of deadwood t, and in proper operative position with respect thereto and with respect to the rudder l I. The auxiliary power unit is therefore moved to the position just described Whenever it is desired to use it for pro pelling the boat either with or without the sail.

When it is desired to operate the boat by means of the sail alone, the engine is stopped and the blades of propeller 2 are set in vertical position so that the propeller will be in alignment with recess 1. This may be accomplished with the aid of an index mark on the shaft or flywheel and a corresponding mark on the frame of the engine. Engine unit l is then shifted forward to the dot and dash position by hand thereby at the same time moving propeller 2 forward into recess 1. In this recess no part of the propeller or propeller shaft projects outside of the deadwood section 6 of the keel. Consequently the boat can be operated under sail without the influence of propeller drag. Moreover since the propeller substantially fills recess 1, there is no opporunity for drag produced by eddy currents within such recess.

In order to provide for the fore and aft shifting of the auxiliary engine unit I, it is mounted on a pair of longitudinally extending slideways l2 which are appropriately secured to the frame members of hull 4. A pair of L-shaped sliding supports [3 may be bolted underneath the supporting lugs M which are provided at each side of the engine unit. In order to secure the engine in either of the positions to which it is desired to operate it, hand screws [5 may operate in threaded openings in each of the sliding supports I3, the inner ends of these screws being received in apertures which are provided in the outside surfaces of ways [2. If these ways are made of wood, it is preferable to provide metal strips, one of which is indicated at [6 in Fig. 3, to receive these holes.

The modification shown in the lefthand half of Fig. 4 is intended for use with boats of a larger size than that previously described and which require a higher powered engine which must be mounted in fixed position in the boat. Such engines are usually equipped with a combined clutch and reversing gear which is indicated by numeral I! in Fig. 4. Coupled to the rear end of the engine shaft, for example by means of a flanged coupling 18, is the driving member I9 of a telescoping, power-transmitting joint indicated generally by numeral 20. Propeller shaft 3a constitutes the driven member of this power-transmitting joint or connection.

The telescoping joint of connection may be made in any suitable form, but for purposes of illustration the forward end of propeller shaft 3a is made to telescope within the driving member l9 which is of tubular form and provided with an elongated slot 21 within which fits a driving pin 22 which is secured crosswise near the forward end of the propeller shaft as shown in Fig. 5.

The employment of this longitudinally shiftable connection or telescoping joint 20 allows the propeller shaft 3a to be shifted fore and aft to move the propeller 2 to either the operative position shown in full lines in Fig. 4, or to the retracted position shown in dotted lines where the propeller is received within recess 1.

This longitudinal movement of propeller shaft 3a may be accomplished in a simple manner by providing a collar 23 which is permanently fixed to the shaft near its forward end and at the rear of a bearing 24 which may be provided for the rear end of the driving member I9 of the telescoping connection 29. The longitudinal movement of shaft 3a is accomplished by the employment of a hand tool 25 which is provided with a forked portion 26 at its lower end. In using this tool the forked portion is placed astraddle of shaft 3a and the lower ends of the fork are brought into engagement with prying surface 21. This prying surface may consist of a bar 28 having cross ridges or teeth on its upper surface, or

it may consist of a member having its upper face roughened in any suitable way to enable a purchase to be obtained by means of the forked lower end of tool 25. By engaging the lower end of the tool with the prying surface 21 and bringing the upper portion of the forks 26 against collar 23, shaft 3a can be forced in either direction, the tool being moved along the prying surface as the shaft is moved. In Fig. 4 tool 25 is shown in full lines in position to start the shifting of shaft 3a and propeller 2 towards the left, and the dotted position of tool 25 indicates the final motion of the shaft, which brings the propeller into its recess 1.

While the invention has been illustrated in two embodiments thereof, it will be understood that other changes can be made in the detailed arrangements in keeping with the purpose of the invention, and it will be further understood that the scope of the invention is intended also to cover such changes as come within the scope of the appended claims.

I claim:

1. In an auxiliary-powered sailboat, a hull having a deadwood structure, an engine within said hull, a propeller shaft channel extending lengthwise of said deadwood structure, a propeller shaft within said channel and extending from said engine rearwardly, a propeller mounted in operative position on the rear end of said shaft, a propeller-receiving recess in the end of said deadwood structure adjacent said channel, and means Within said hull for supporting said engine for shifting movement in a fore and aft direction, said engine when shifted rearward carrying with it said shaft and moving said propeller to operative position beyond the rear end of said deadwood, said engine when shifted forward carrying the propeller into said recess.

2. In an auxiliary-powered sailboat, a hull having a deadwood structure, an engine within said hull, a propeller shaft channel extending lengthwise of said deadwood structure, a propeller shaft within said channel and extending from said engine rearwardly, a propeller mounted in operative position on the rear end of said shaft, 2. propeller-receiving recess in the end of said deadwood structure adjacent said channel, and a slideway structure mounted in fixed position longitudinally of said hull for supporting said engine, said engine being shiftable in a fore and aft direction on said slideway, said engine when shifted rearward carrying with it said shaft and moving said propeller to operative position beyond the rear end of said deadwood, said engine When shifted forward carrying the propeller into said recess, and means for securing said engine in either said rearward or forward position.

EARL O. HURST.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 598,337 Ferguson Feb. 1, 1898 1,099,821 Riggin June 9, 1914 1,923,995 Nook Aug. 22, 1933 2,524,184 Wiggins Oct. 3, 1950 FOREIGN PATENTS Number Country Date 750,402 France May 22, 1933 

